1. Technical Field
The present disclosure relates to plugs, and more particularly to a built-up plug.
2. Description of Related Art
Two-phase plug or three-phase plug is used in electronic device, and is engaged with two-phase jack or three-phase jack. The two-phase jack is needed when two-phase plug is used. The three-phase jack is needed when three-phase plug is used. However, if only has a three-phase jack when two-phase plug is mounted in electronic device or just have a two-phase jack when a three-phase plug is mounted in electronic device, the plug will not engage with the jack.